Continuous process for the manufacture of hard sweet dough



May 18, 1965 M. c. HARRIS ETAL CONTINUOUS PROCESS FOR THE MANUFACTURE OF HARD SWEET DOUGH INVENTORS M5405 C. .HQRQ/S United States Patent C) Fice CNTNUOUS PRCESS FR THE MANUFAC- TURE GF HARD SWEET DGUGH Meade C. Harris, Rutherford, NJ., and Elmore F. Maehl,

deceased, late of Fanwood, NJ., by Eunice Maehl, legal representative, Fanwood, NJ., assignors to National Biscuit Company, a corporation of New .lersey Filed Apr. 23, 1963, Ser. No. 275,165

11 Claims. (Cl. 99-90) This invention relates to the art of mixing and more specifically to a continuous process for mixing, which delivers a continuous stream of properly mixed and homogeneous material to the next reaction zone.

Although the invention is not limited to the baking industry and may readily be applied to other processing industries and to several other items of the food and baking industry, the invention is specically useful with hard sweet goods, that is with doughs of high viscosity in which the amount of diluents, for instance water or milk is below the usual amount of other baked products, and the proportion of sugar is above 12% of the finished goods.

lt has long been recognized that proper mixing of the ingredients prior to the baking stage is essential in practically all baked goods, for the attainment of a homogeneous product having desired characteristics of grain structure, texture, moisture content, flavor and color. Except for the process described in United States Patent 3,057,730, thorough mixing of all ingredients has been considered fundamental in the art.

In the commercial production of baked goods, satisfactory results have been achieved by the use of batch mixing equipment. It is clear, however, that where tons of material are to be mixed at one time, this equipment requires large floor space, is expensive in initial cost, and has high power requirement and high maintenance and replacement cost.

The continuous system on the other hand has a very high capacity relative to the size of the mixing unit, because it operates on smaller volumes than batch systems at any one time so that lower horsepower installations are permissible. Batchwide operation is more suitable where it is not possible to measure the amount of each ingredient carefully and where diiferences in composition of our may give rise to unforeseen changes in consistency during mixing, because each batch may be processed for a different length of time or adapted during operation to different conditions. It is safe to conclude that whenever possible, cost-minded manufacturers have shifted to continuous processes because the machines are smaller, may be built throughout of the more expensive corrosionresistant material, and because of more effective use of the power.

In recent years some successful results have been claimed with continuous processes for mixing doughs, batters and even bread doughs. For instance U.S.P. 2,953,460 covers a continuous process for the preparation of bread dough. U.S.P. 2,920,964 discloses and claims a process for the continuous preparation of soda cracker dough, U.S.P. 3,041,176 describes a process for the continuous mixing of Hour into a slurry in a conll Patented Mery 18, 1955 tinuous mixing machine and continuously injecting a gaseous medium to aerate the slurry and to produce a risen dough, after the gas is allowed to expand.

No serious diiculties have been encountered in the art in the conversion from a batch to a continuous process, where simple blending of thin liquids and dry powders is involved. Where the diluent is present at least to the extent of 35% of the dough, as in the doughs involved in U.S.P. 2,953,460 and U.S.P. 2,920,964, continuous mixing of the ingredients has been feasible. Also in U.S.P. 3,041,176, a high proportion of water is continuously added to the fiour, and in addition, gas is injected such as air or carbon dioxide, so that the mixture of ingredients is maintained suiciently thin during mixing.

The processes and equipment described and claimed in these above-mentioned patents would not be successful with hard-sweet goods, because the dough is far more viscous than the usual batter, and contains no more than 12% of water, and as low as 6.5%, based on the total dough composition, not including water present in flour and other ingredients.

Whatever is the situation with sponge and bread dough, suice it to say that no progress had been made prior to the present invention in the art of continuous mixing hard sweet doughs, that is hard doughs of high viscosity. Here, mixing even on a batch scale is a problem, and the manufacturer has been concerned with devising equipment at least suitable for batch operations. With attention centered in devising equipment suitable for each individual specific process, on a batch scale, little or no theory was available, prior to this invention, which might have led to any quantitative and systematized approach to the mixing on a continuous scale. Continuous mixing of hard sweet doughs was considered out of reach by the man in the art.

Admittedly some manufacturers have marketed and advertised equipment for continuously mixing hard-to-mix materials, and thermoplastic solids. These devices called masticators or continuous kneaders or extruders, are claimed to be successful with several types of hard materials. However, in our experience with hard sweet doughs, they proved far from satisfactory. Some experiments were conducted by using a combination of gravimetric and volumetric-type feeders. Flour, soda, ammonium bicarbonate were blended and discharged into the mixing zone. Other dry ingredients, namely, sugar, cocoa, egg powder, were blended and fed into the premixing zone. Liquid ingredients, lard, water, eggs, corn syrup, stored in individual holding tanks, were pumped into the premixing zone and then the mass discharged into the mixing zone. A combination of helical screws and angularly positioned paddle blades rotating at about rpm., worked and moved the resulting mass. The time of mixing from the inlet end of the mixing zone to the discharge end was 2.5 minutes, with a rate of 3000 pounds per hour. The resulting doughs were soft and sticky suggesting that kneading was inadequate, and that hydration of the dry solids was not homogeneous. It was found to be advantageous to use a second kneader, to give additional working and mixing of the dough. Under these conditions, sufficiently uniform hydration and sufticient body was achieved so that a lay time of l5 to 30 A major difculty, however, was that after a short period of operation the dough temperature began to rise due to mechanical heat development. Refrigeration was essential, necessitating a I-LP., 15 tonrper day capacity, circulating refrigeration system. Forrnore eficient refrigeration, two air-cooled .1% H.P., Freon ciry culating units had to be installed. On occasions, during hot weather, a third 1'1/2 Hl. refrigerating unit was used.

`Although` this process was significant as a first attempt Y in the continuous manufacture of hard sweet doughs, it is obvious that as a Whole, it was far fromv satisfactory. The cost involved in the refrigerationv was substantiaLit still needed a lay-time, and in any event the processcould ,not be run on Va Vtruly continuous scale, but could only befrun for short periods of time and required justv asmuch attention as any 'batch process. Y

It has now been found that it is'possible to prepare the hard sweetV dough by a continuous process andato supply a continuous stream of uniformly blended and kneaded dough to jthe oven without interruption and(y without undue development of heat. Thus the `present invention represents a revolutionary advance in an art, that is, manufacture ofrhard sweet dough, where continuous. mixingV was considered an impossibility. "One object of the present inventionV is to provide for the continuous manufacture of hard sweet dough in a satisfactory and practical manner so asgto deliver tothe oven a continuous stream of fully mixed dough. Another object is to overcome the disadvantages andl deficiencies Vwhich have interfered with the continuous preparation of hard sweet dough` mixes.

Another objectof the present invention is to provide (3) Separately melting and weighing accurately the amount of shortening andy continuously discharging at a predetermined rate some shortening yinto the mixing-zone, Y

' (4) Separately mixing the aqueous phase ingredients, for instance eggs, or egg powder, leavening agent,.malt

extract, invert syrup, milk vor milk substitute, that is adding the water-soluble ingredients to the aqueous phase, in accurately weighed amounts, to form a slurry and `continuously discharging thev slurry into the mixing zone, at a preselected rate,

(5) Continuously and uniformly blending the slurry withthe dry material mix and the` shortening with the minimum temperature rise, Y

(6) Continuously discharging the blend into a mixing Zone where the mix is subjectedrto kneading and shearing to produce a homogeneous well-kncaded dough with the minimum temperature rise,A

(7) Controlling the rate of dough advancing to the next zone, that is the cutterV or the oven. w

For the sake of clarity, dough means a mixture, of our'and waterrand usually other optional ingredients, thick enough to knead or roll. The term hard sweet dough comprises generally all the yformulations of our, sugar, Water, and/or milk and a' shortening, as the es: sential ingredients, with a chemical as aleavening agent. Some optional ingredients may be present,depending on the formulation, for instance coloring or flavoring agent, cocoa, eggs, and the like. The sugar content4 of the hard sweet goods within the scope of thisrinvention is high, *Aat least.12% and. as lhigh las 21% of the total compostion. The amount of added water or in general of a diluentin the hard sweet goods is lower than Y in the usual batters, because it is never over 12% and a Vprocess whereby ahard sweet dough may be producedV uniformly, in reproducible manner with fewer steps, and Y less labor thanheretofore in the baking industry.

Another object of this invention is to provide a process which permits the preparation of hard sweet dough at greatly reduced cost, with less equipment, less spacefgr the equipment VVand which requires less attention than the common batchroperations. Y

Still another object is to provide a process which gives improved finished products with easily reproducibleV qualities of texture, flavor and appearance.

i A fundamental object of the invention is to provide` a process which insures the feeder discharge of accurately predetermined amounts of the materials through out each period ofthe operation.

Another objecty is to provide a type of feeder which can weigh materials continuouslyand which continuously records the weight of the material which has been discharged. Y v Still a further object is to provide a process in Vwhich the dry and wet ingredients blend thoroughly before any kneading and shearing action is applied.

, y Another object of this instant invention is to avoid' the lay-time, which in addition to delaying the operation, causes changes in the consistency of the dough if samples are compared at different intervals of time after the beginning of the operation.

The present invention involves inherentlyV simple operationsbut in such `a combination and sequence that it monopalmitim may be used. Optional water-soluble inhas permitted the achie'vementrof the improved and novel f process. y

More specifically the present'iuvention comprises:

(1) Accurately and continuously weighing each ingedient, inusueh a manner that record is kept ofthe material discharged, Y Y (2) Premixing the dry ingredients, our, sugar and Vany other optional dry materialwhich may be used according to specific formulations,

as low as 6.5% of the total` dough composition. The amount of shortening is higher than in the usualdoughs, and is, at ,least 8%V andrup.to15% of thetotalcomposition. i

Thei consistency of hard sweet dough is far higher than in ordinary batters, and other doughs. By way of comparison, bread dough has, a specific gravity less than 1, inthe order of 0.6. 0n the other hand, the hard sweet doughs within the scope lof this invention, have a specific gravity over 1,'usuallybetween 1.1 and 1.5 before lthe goods enter the oven.

The term flour is usedhere with reference to wheat flour, although such flourl as potato ilour, cornY our, and rye flour in Vwhole or in partare also broadly within the scope of the invention.A The our used in the preparationof the Ahard sweet Vdough may have a variable protein content between 7 and 11% of protein, although it is usually preferred to use` weak iiour, that is containing Vbetween 7 and 9.5% of protein, in the preparation of sweet doughs.` As a sweetening agent, cane sugarY of different grade is used accordingw to each individual formulation. Dextrose, lcommercially knownlas corn sugar, mayalso be used. Other types of sweetening agents, available in solution or ,syrup form, for instance invert syrup, 'levulose, honey, corn syrup, malt syrup, may, if the specific formulation calls for, .be addedto the aqueous slurry.` Where optional ingredients are used, they should be blended with either the shortening phase or the dry materialxphase or the-slurry. For instance, if an emulsifier andchocolate liquor are used, they are preferably added vto the shortening. AS an emulsiiier, lecithin or lactylated gredients, such as flavoring agents, are easily dissolved in the slurry. y i i j All essential'feature of the invention is/the combination 'of the water-solubley ingredients in the aqueous slurry. It hasvbeenrfound that the llavor `and color of the baked products, are improved when invert syrup and a milk product are dissolved in water in the presence of an alkaline reagent, usually the soda used as theleaveniug agent,

areaal? It is believed that this effect is the result of a chemical reaction between the reducing sugar and the protein of milk, commonly known as the Maillard reaction. It is to be understood, however, that the scope of the present invention is not to be limited by considerations of speculative nature, particularly because reactions involving proteins are not fully known.

The process of the invention has been thoroughly tested, and at no time the temperature of the material emerging from the mixing zone, where the material is kneaded, is above 106 F. Generally the temperature is lower than 106 F., that is in the range of 90 F. to 96 F., and the temperature in the rst and second mixing zone never rises above 85 F. The temperature rise in the third mixing zone, where the dough is kneaded, may be controlled, if the sequence of steps is properly controlled as described herein. This temperature range, between 90 and 106 F., is very suitable for the next operation, namely the cutting and stamping step.

For a better understanding of the invention, reference may be had to the ilow she-et, FIG. 1, which gives a schematic picture of the process. The dry goods, flour, sugar, and any optional materials, for instance cocoa, are stored in tanks (not shown) so as to maintain a steady supply. From the tanks each material is fed to the bins. Cocoa is one of the optional ingredients shown in the iow sheet under other ingredients. By cocoa is meant the product from the cocoa bean after cleaning, roasting and removing the hull and germ. The cocoa may be either Dutch cocoa, which is made by treating the beans during manufacture with strong caustic potash, or American cocoa or preferably, a mixture of the two, since the avor of very light-colored untreated American cocoa is almost lost in biscuits and cookies.

It is essential to the success of the operation that the amounts of each ingredient be accurately weighed on a continuous basis, rather than measured volumetrically as used heretofore for continuous operations according to the earlier investigations. Accurate control of the amounts of each solid ingredient at this stage permits more reproducible results and has been one of the essential factors in eliminating nonuniformity and the temperature rise in the nal mixing and kneading zone which prior to the present invention, had made continuous operation impractical.

Merchen feeders as described in U.S.P. 2,095,509 and 2,305,484, continuously discharging from the bins accurately weighed amounts of each solid are very satisfactory, but any metering or scale device capable of being vis achieved in the period between l and 30 seconds. An

apparatus with a shaft provided with adjustable blades, revolving at a rate between 350 and 1000 r.p.m. is satisfactory, and the temperature usually remains below 85 F.

Anydevice for conveying material may be used from the tanks to the bins, and from the bins to the mixer, for instance, screw conveyors, belts, rotary feeders, provided with a controllable gate or valve. It has been found particularly advantageous to use vibrators, after the material has been weighed because they provide for complete discharge with no hold up. The dry blended materials are then led to the second mixing zone, shown in the ilow sheet as Mixer No. 2.

As a shortening, all-hydrogenated lard or butter may be used as well as vegetable oils, oleo oils, coconut and palm oils. Incompletely hydrogenated lard or cottonseed, corn and peanut oil may also be used in different formulations. From a flavor standpoint and Where long stability is not of the essence, butter is excellent as a part of the shortening in many sweet goods.

Although we have had very satisfactory results with lard, it is to be understood that the selection of the shortening or butter or a combination of both is not a limitation on the process, but depends upon each individual formulation. In some instances, the hard butters of commerce may be substituted in whole or in part. The term hard butters indicates the products of interesterification and rearrangement of natural fats or mixtures of same which is believed to cause a random distribution of the fatty acid radicals in the triglyceride units. For the nature of the process of interesterification and the ran-` dom distribution of the products, reference is made to Gilman, Advanced Treatise of Crganic Chemistry, vol. HI (1953), chapter on Lipids, p. 186. If the shortening or hard butter used is in the solid phase, at room temperature, provision is made (not shown) to provide moderate heat sufficient to melt the solid. Also the shortening is continuously weighed and led into the second mixing zone, by means of a metering pump.

The third phase, that is, the aqueous phase or as it is more usually called the slurry, contains water, a leavening agent, salt and may contain also milk or a milk substitute, invert syrup, levulose, according to the specific formulation and eggs, or egg powder. All these ingredients are carefully measured and dissolved or suspended in water in the slurry mixing tank. A metering pump accurately measures the rate of discharge of the slurry to the second mixing zone.

Leavening agent is the term used in the art to indicate a source of gas which causes a dough or batter to spring, giving a porous, open structure to the product. Several chemical agents may be used as leavening agents as -described in Bohn, Biscuit and Cracker Production, American Trade Publishing Company (1957), pp. 19-22. Very satisfactory results have been obtained with sodium bicarbonate, alone, since it decomposes during baking to 'give the desired carbon dioxide.

It is preferred to have all the elements of the apparatus subject to remote controls, to permit the operator to follow and regulate the course of the mixing. The table below gives variations in specific formulations of hard sweet goods, classied according to the sugar content and based on the ratio of each ingredient to flour. Thus the table shows a Low-Sugar," a Medium-Sugar and a High-Sugar content formulation. t is to be understood, however, that the three formulations are given by way of illustration, and that broadly the hard sweet goods, within the scope of the invention, may only contain the three basic components, flour, sugar and a diluent, which is a shortening and water. Thus the term hard sweet goods within the scope of this invention broadly comprises formulations containing between l2 and 21% of sugar, between 6.5 and 12% of added water, and between 8 and 15% of shortening, these percentages being expressed with reference to the total dough composition.

Referring now to the three formulations shown in the table, variations are possible not only from one formulation to the other, but by the omission or addition of some ingredients. For instance, the use of an emulsier, which is another' optional ingredient, has not been shown in the three formulations in the table. As indicated above, the amount of water, between 6.5 and 12%, is the added water, and does not include water present, for instance, in flour and other ingredients.

a, i e4, a 1 'r Low sugar Medium sugar High sugar Y Lbs. No. of lbs. Lbs. N o. oflbs. Lbs. No. oflbs. Y per hr. per hr. r per hr.

Dry materials: Y Y, Y

Flour 100 2, 000 1 00 2, 000 100 2, 000V Sugar 21 420 33 660 47 940 Cocoa 20 400 shortening 500 16. 5 330 1 1.8 5 370 Slurry: l

Liq. sugar 3 60 3 60 9 180 Eggs 8 60 3 60 Milk. 1. 25 25 1. 25 25 2. 5 50 Salt 1 20 1 20 1. 25 .25 Leavening. 1 V20 1 20 3 60 y Flavor 0.06 1. 2 0. 25 5 1. 5 30 Water 12 2A0 13 260 25 500 Total slurry-; 21. 3l 426. 2 22. 50 450. 42. 25 845 Total Welght. 167. 3l 3, 346. 2 172. 0 3, 440 227. 75 4, 555

other ingredients varied. VAlthough inthe table, the High- Sugar formulation shows that cocoa is used, where a chocolate flavor is desired, it may be possible at least partiallyY to replace the cocoa with chocolate liquor. v In this case if the cocoa is cut down to one-half,V that is, 10 pounds of cocoa instead of 20 pounds,the amount of chocolate liquor is 3 to A5 pounds per'100 pounds of ilour. In other Words, the chocolate liquoris added at a rate of l to 1.8 pounds per minute.

For the successful operation of the process, the adjustment of the feeding devices of all ingredients, the rate of discharge from each mixing zone, and rate of discharge at the outlet` of the third mixing zone, must be carefully controlled for each formulation. By Way of illustration, and with reference to the threej formulations shown in the table, the rate of feeding flour is kept con-r stant, namely 33.33 pounds per minute, equivalent to 2000 pounds per hour. Flour may be partly supplemented with meal, that is recovered material from prior preparations, usually material rejected because broken into y' small pieces. Also different grades of flour or types of flour may be required, according to specic formulations. With a llour feed at the rate of 33.33 pounds per minute, the sugar rate must be adjusted to 7 pounds per minute in the low-sugar formulation, 1l pounds per minute in the -mediuIn-sugar formulation and 15.66 pounds per minute in the high-sugar formulation. When cocoa'is added, as in the high-sugar formulation,` the rate of feeding is 6.6 pounds per minute.

The rate of feeding of each ingredient Ifor the three formulations shown in the table is obviously'easily derived by dividing the total number-of pounds of each ingredient per hour by 60.- For instance the total number of pounds of aqueous slurry'added per minute for each formulation is obtained by dividing the total'number ofrpounds of aqueous 'slurryper hour by 60. Thus, by way of example,

per minute for the Medium-Sugar formulation and 845/60, `that is, 14.08 pounds per minute in the High-Sugar formulation.

The amount of salt in the low and medium sugar formulation is 0.33 poundy per minute, and 0.41 pound per. minute in the high-sugar formulation. The amount of milk is preferably 0.41 pound per minute in the low y and medium sugar formulation and 0.83 pound per minute in the high-sugar formulation. Invert syrup and malt extract, schematically represented in the diagramas liquid sugar, yare fed into the aqueous phase at a rate 1 pound per minute in the low and medium vsugar formulation, and 3 pounds per minute inthe high-sugar formulation.

The amount of water ispumped at arate of 4 pounds per minute in the low-sugar formulation, 4.3 pounds per minute inthe medium-sugar formulation and 8.3 pounds per minute in the high-sugar formulation.

The amount of flavoring agents varies 'from 0.02 pound minute, the rate of discharge of dry solids from Mixer in the medium-.sugar formulation 44 lbs..per.minu`tevand in the high-sugar formulation 55.7 lbs. per minute. Y As the'ilow sheetindicates, the dry solid phase, the liquid slurry and Vthe shorteningV phase are continuously fed into the second kmixing zone, namely Mixer No. 2. Here it is essential that good` blending of the dry ingredients, slurrygand shortening, be achieved with a resildence time .between 1 and 30 seconds; This may be vachieved with an'apparatus in which ythe rotatable .shaft or'other mixing elementrevolves atga` rate between 350 and 1000 r.p.m.V preferably 720 r.p.m. If the conditions are carefully controlled,vthe temperature in thefsecnd mixing zone never rises above 85 F.Y Satisfactory results have been 'achieved with the mixer marketed by Ambrette Machinery Corporation, under theV name of Cyclomixer.

although the invention is not limited to any particular apparatus, Vas long as good blending of dry ingredients, liquid ingredients and shortening is achieved, in the .same Vperiod of time, that is l to 30 seconds..

From the second mixing zone,'the"material is led to the third mixing zone, shown as Mixer No. 3V wher/eeffieient mixing and kneading occurs. By way of illustration and with reference to the three` formulations given in the table, the rate ofdischarge from'the second mixer in the lowsugar formulation is 55.76 pounds per minute, 57.43 pounds per minute in the medium-sugar formulation, and 75.91 pounds per minute'n the high-sugar formulation.

In the third zone, which is shown in the ow sheet as rMixer No. k3, all the materials Vrnust react with water to give uniform hydration, which is essential'for the achievement of a homogeneous dough.

It has now been found that homogeneity vof the dough and uniform hydration may beY achieved inthe kneading zone withV a residence time between 30 seconds and 3 minutesY 70 One type of apparatus used successfully in this kneading `step is aslow speed mixer-extruder with shaft preferably adjusted at 40 r.p.m., although the rate of revolution may be adjusted within the range of 30 to 90. r.p.m.

Although the invention is not limited to any specific make of extruder or type of shaft, very satisfactory results No. 1 inthe lowsugarformulation is 40 lbs. per minute,l

ansa-,sri

Q were obtained with the mixer-extruder manufactured by the Reitz Manufacturing Company described here. The apparatus comprises a cylindrical housing and is provided with a rotatable shaft and cut-olf blades o-n the shaft to mull and slice the material.

In order to provide additional kneading action, at least one and preferably two screens are positioned in the interior of the extruder, atlixed to the inner walls of the housing. It was also found advantageous to attach to the inner walls of the apparatus at least a pair and preferably four plows disposed at diametrically opposite points in the inner part of the cylinder. These plow blades, inserted between the rotating blades, act as stationary anvils, and greatly contribute to kneading and fully developing the dough. The material is fed into the housing at one end, forced forward by the rotating blade onto the anvil. As the blade passes the anvil, a portion of the material is pushed forward and the remainder stays behind subject to repeated kneading action. The extrusion head is provided with a nose cone which gives additional blending and kneading action, thus insuring the production of smooth, properly kneaded, uniformly hydrated material.

It is significant that by the proper combination of steps, as described herein, it has been found unnecessary to cool by external refrigeration in any of the mixing or kneading steps, namely the first or second mixing zones as well as the extruder. The temperature at no time rises above 106 F., and is usually below 96 F. The temperature in the iirst and second mixing zones, namely Mixer No. 1 and Mixer No. 2, never rises above 85 F., if the steps are conducted in accordance with this instant invention. The severe kneading treatment carried out in the third zone, that is the mixer-extruder, converts the preliminary blend to a putty-like homogeneous non-sticky dough, Well kneaded, of uniform hydration throughout. From the mixer-extruder the material advances at a predetermined rate towards the cutting and the stamping zone, and then to the oven. The rate of discharge, by way of illustration, is 55.76 pounds per minute in the low-sugar formulation, 57.43 pounds per minute in the medium-sugar formulation, and 75.91 pounds per minute in the high-sugar formulation.

For the purpose of better illustrating the invention, the following examples are described in detail.

Example I A blend of wheat our (protein content 8.5%) and sugar was continuously prepared by passing liour at the rate of 2G00 lbs. per hour, corresponding to 33.33 pounds per minute and sugar at the rate of 7 pounds per minute in the first Mixer, with a residence time of 10 seconds, and shaft set at 650 r.p.m.

Lard was fed to second Mixer at a rate of 8.3 pounds per minute.

The aqueous slurry was separately prepared on a batch scale, although it may also be prepared on a continuous operation. On a batch scale, the materials sufficient for a 4 hour run were mixed, namely, 960 pounds of water, SO pounds of salt, 24() pounds of egg powder, 100 pounds of milk, 80 pounds of leavening agent, 4.8 pounds of vanilla and 240 pounds of invert syrup. The aqueous slurry, thus prepared, was fed to the second mixer at a rate of 7.1 pounds per minute.

The dry material blend was discharged from the first mixer at a rate of 4() pounds per minute. A satisfactory blending of the three phases, shortening, dry materials and aqueous slurry was achieved in the Cyclomixer, sold bythe Ambrette Machinery Corporation, with a residence time of 10 seconds, and shaft rotating at 720 rpm.

This blend was removed from the Cyclornixer at the rate of 55.76 pounds per minute, and passed to the Mixer- Extruder, specifically the Extruder manufactured by the Reitz Manufacturing Corporation, where the residence time Was 2 minutes. The temperature in the Extruder remained throughout the operation lat 95l00 F. The material was removed from the Extruder at the rate of fed into the iirst mixing zone.

l@ 55.76 pounds per minute. It was then subjected to a cutting device, and baked. The resulting goods after 120 hours of the continuous operation were of excellent quality, tender and homogeneous. The output was 3346 lbs. per hour.

Example 2 Flour (of protein content 9.5%), at the rate of 33.33 pounds per minute, and sugar at the rate of 1l pounds per minute, were mixed in the first mixer where the residence time was 30 seconds. The shaft was rotated at a speed of 650 rpm. The rate of discharge of the dry solids to the Cyclomixer was 44 pounds per minute. Shortening, namely lard, was discharged into the Ambrette Cyclornixer at a rate of 5.5 pounds per minute.

The aqueous slurry was prepared by combining 1040 pounds of water, 100 pounds of milk, 80 pounds of salt, 8O pounds o-f leavening, 20 pounds of vanilla, 2.4() pounds of liquid sugar, 240 pounds of egg powder, that is the ingredients required for a 4 hour operation. The aqueous slurry -was discharged into the Cyclomixer at a rate of 5 .5 =pounds per minute. The residence time in the Cyclomixer fwas l5 seconds, and in the Reitz extruder, that is the lthird mixing zone, it was 2.5 minutes. The tempera` ture in the Reitz extruder did not exceed 95 F., and remained mostly between 90 and 92 F., throughout the operation of 90 hours.

After cutting and baking, the goods were crispy, light, homogeneous in flavor, appearance and weight. There Was no change in the quality of the finished goods Aat the end of the operation, which gave an loutput of 3440 pounds per hour.

Example 3 Flour at a rate of 33.33 pounds per minute and sugar -at the rate of 15.66 pounds per minute were continuously Cocoa was sieved, cooled to below 70 and fed to the same rst Mixer at a rate of 6.6 pounds per minute. With a residence time of 15 seconds and with a shaft rotating at 690 r.p.m., a good premixing of the three -dry ingredients was achieved. The dry solid-s were ifed into the Cyclomixer at a rate of 55.6 pounds per minute.

Lard was fed into the Cyclomixer at a rate of 6:1 pounds per minute. The aqueous slurry was prepared in a batch for a 4 hour operation, namely 2000` pounds of water, 720 pounds of invert syrup, 200 pounds of milk powder, 10G p-ounds of salt, 240 pounds of leavening, 120 pounds of vanilla. in the Cyclomixer, the ydry solids, the slurry and shortening were blended with a residence time of 20 seconds and fed Iinto the extruder at a Irate of 75.91 pounds per minute. The residence time in the extruder was 1.5 minutes,twith a shaft rotating at 46 r.p.m. The rate of extrusion Ifrom the extruder was .91 pounds per minute. The mixing was continued for 7() hours, with an output of 4555 pounds per hour, giving a very satisfactory homogeneous dough.

Although not shown in the table or in the diagram, an edible emulsiiier may be added either to the shortening or to the aqueous slurry, in amount of 'l to 4 ounces per 1GO pounds of flour. As edible emulsiiier, lecithin or glyceryl lacto palmitate may be used, manufactured by Atlas Powder Company.

As a further proof of the 4function of each step of the process in accordance with the instant invention, :and particularly the function of Mixer No. 2 and the function of Mixer No. 3, moisture content determinations have been performed with the Low-Sugar, Medium-Sugar and High-Sugar formulations. The moisture content determinations were conducted by the toluene test, by remov- :ing samples of dough at the outlet of Mixer No. 2 and also Mixer No. 3. The samples were removed at uniform time intervals, as well as several samples were simultaneously removed from the same zone. The moisture content was the same, within the limit of experimental error, thus indicating that blending of water with the other ingredients is `achieved in Mixer No. 2, and that i areaal? the vMixer No, 3 d-oes not contribute to the uniform'distribution of'the water, and -other ingredients. On the other hand, the dough at the outlet of Mixer N-o. 2 thas thek appearance and texture of coffee ground, thatris, -although well blended, has no body. jA-s'ii: leaves Mixer No. 3, |the dough has putty-like Iappearance and isf'well kneaded, indicating that the function of Mixen No. 3 is to cause uniform hydration of the dough.

From'the foregoing, -itmaybe seen that this inventionV prior to cutting, stamping and baking. Departures from,

the speci-o illustrations given herein are within the scope of the invention, which is to be limited `only bythe ap-v pended claims.

Y What is claimed is;

1. The continuous process -kfor the manufacture of hard sweet doughs which contain between 12 land 21% of sugar, which comprises: Y

(a) continuously feeding into a mixing zone, yflour* atV 4555 pounds per hour.

a rate ofl 33.33 pounds per minute, sugar at a rate'V between 7 and 16 pounds per minute, cocoa at av rate between and 6.6 pounds per minute mechani (b) feeding into said second mixing zone shortening-at' a rate of to 9 pounds per minute and a slurry,A

which is continuously prepared from water at a rate between 4 and 8 pounds per minute, invert syrup between l Iand 3 pounds per minute, milla'between 0.4 and 0.8 pound yper minute, sait between 0.4 and 0.4 pound per minute, a leavening agent between 0.3 and 1 pound per minute, and flavoring `agent between 0.02rand 0.5 pound per minute mechanically agitating and forming Va mix of said `slurry, said shortening, and said dry ingredients in said ysecond mixing zone, with a residence time between 1 and 30 seconds at aV temperature not exceeding v85 F. and discharging said mix at a rate of 55 to 76 pounds per minute into a third mixing zone, y Y (c) kneading said mix in Asaid third mixing zone to give uniform hydration .of sai-d Vingredients with la residen-ce time of Iseconds to 3 minutes .at a temperature not exceeding 106 F. and discharging said dough from -saidkneading zone at a rate of 55 to -76 pounds per minute. 2. The process accordingto claim l wherein lecithin is `added to said shortening in amount between land 4 |ounces per 100 pounds of our.

3. The process according to claim 1 ywherein said sh-ort-V ening is present in the proportion of 8 to 15% of said doughs, and said doughs have a specific gravity between- 1.1 and 1.5, and a continuous -ow of kneaded Vdough is 12- fed to the next reaction zone .at a rate between 3346 and 4; The rprocess yaccording to claim wherein a mixing element rotates in said 4iirstand said second mixing zones at .a speed between 350 and 1000 r.p.m. and a mixing v element rotates in said third khea'ding'zone at a speed of between 30 and 90 rpm. A Y 5. The continuous process of mixing the dough of hardsweet goods which comprise as dry dough ingredients wheat flour and sugar, and as diluents, water and 'shortening, vand -other water-soluble ingredients, said water being `present in amount not exceeding 12% of the total dough composition, which comprises: c y

(a), continuously feeding `each of said dry dough ingredients; at -a predetermined rate int-o arst mixing zone where said ingredients are agitated and mixed with a residence time between 1 and 30 seconds, `at

f :a temperature not exceeding 8,5 F. Y

(b) continuously, feeding said K4water and said watersoluble ingredients at a predetermined rate, into a common receptacle, whereby an vaqueous slurry is -continuously formed, l y o y (c),'continuously Vfeeding said shortening and said dry solid mix'and said aqueous slurry into Ia second mix- -ing zone, and mechanically agitating, whereby -a uniform blend is achieved, at a temperature not exceeding F.with a residence time between 1 and A30 seconds, ,2 Y i (d), continuously dischargingsaid blend to a kneading z-one, continuously kneading said blend at a temperature` not exceeding 106 F., whereby a uniformly hydrated dough is obtained with a residence time `between 30 seconds and 3 minutes. l

6. The process according to claim 5 wherein each of said ingredients is continu-ously weighed.

7. The process according 1to claim 5 wherein said first mixing zone is adapted to receiveaplurality, of dry solid components, and at least a member selected fromjthe groupiconsisting ofcocoa, corn 'ii-our, potato onrrand rye our is discharged at a predetermined -rate into said rst Amixing zone, 'simultaneously with said sugar and wheat per 100 pounds of lour.

11. The process according to claim 5 wherein the temperatnre in said kneading zoneris between 90 and 96 F.

References Cited by the Examiner UNITED STATES PATENTS 2,953,460 9/60 Baker.

3,041,176 6/6'2 Baker 99--90 3,057,730 10/62 Morck 99-92 X 3,108,878 1'0/ 63 Higashiuchi et al. 99-90 A. LOUIS MONACELL, Primary Examiner. RAYMOND N. J ONES, Examiner. l 

5. THE CONTINUOUS PROCESS FO MIXIG THE DOUGH OF HARDSWEET GOODS WHICH COMPRISE AS DRY DOUGH INGREDIENTS WHEAT FLOUR AND SUGAR, AND AS DILUENTS, WATER AND SHORTENING, AND OTHER WATER SOLUBLE INGREDIENTS, SAID WATER BEING PRESENT IN AMOUNT NOT EXCEEDING 12% OF THE TOTAL DOUGH COMPOSITION, WHICH COMPRISES: (A) CONTINUOUSLY FEEDIG EACHOF SAID DRY DOUGH INGREDIENTS, AT A PREDETERMINED RATE INTO A FIRST MIXING ZONE WHERE SAID INGREDIENTS ARE AGITATED AND MIXED WITH A RESIDENCE TIME BETWEEN 1 AND 30 SECONDS, AT A TEMPERATURE NOT EXCEEDDING 85*F. (B) CONTINUOUSLY FEEDING SAID WATER AND SAID WATERSOLUBLE INGREDIENTS AT A PREDETERMINED RATE, INTO A COMMON RECEPTACLE, WHEREBY ANAQUEOUS SLURRY IS CONTINUOUSLY FORMED, (C) CONTINUOUSLY FEEDING SAID SHORTENIG AND SAID DRY SOLID MIX AND SAID AQUEOUS SLURRY INTO A SECOND MIXING ZONE, AND MECHANICALLY AGITATING, WHEREBY A UNIFORM BLEND IS ACHIEVED, AT A TEMPERATURE NOT EXCEEDING 85*F., WITH A RESIDENCE TIME BETWEEN 1 AND 30 SECONDS, (D) CONTINUOUSLY DISCHARGING SAID BLEND TO A KNEADING ZONE, CONTINUOUSLY KNEADING SAID BLEND AT A TEMPERATURE NOT EXCEEDING 106*F., WHEREBY A UNIFORMLY HYDRATED DOUGH IS OBTAINED WITH A RESIDENCE TIME BETWEEN 30 SECONDS AND 3 MINUTES. 